Questions tagged [voltage-level]

Voltage level should be used for questions that are referring to using hardware together that operates on different voltages (the "concentration" of electricity).

Filter by
Sorted by
Tagged with
21 votes
4 answers
8k views

How can higher current devices (motors, solenoids, lights, etc.) be controlled by an Arduino?

I'm looking for a broadly applicable solution, one that can be adapted to a variety of projects. I'm currently working on several projects that each require controlling devices ranging from 800mA to ...
jlbnjmn's user avatar
  • 978
61 votes
4 answers
263k views

What are the 5V and VIN pins for?

I believe I can supply the Arduino with power in three different ways: Use USB. The design trusts the 5V to be regulated, and does not regulate it in any way. Use a regulated power source, trusted ...
Mads Skjern's user avatar
  • 1,125
3 votes
1 answer
15k views

best way to protect a digital or analog input from 12volts

At work, I have connected an Arduino to a security key (which has a 12v power supply) in order to give us a more versatile door lock. Unfortunately, people keep removing the key pad, disconnecting ...
Hoytman's user avatar
  • 747
4 votes
1 answer
6k views

How to switch an external circuit with Arduino?

I have an object with a series of led and I want to turn on and off these leds from my Arduino. The input of the LED circuit is 24v DC 100mA. What I've done is the following: I've cut a wire of this ...
Alessandro's user avatar
0 votes
1 answer
1k views

How to read a higher voltage digital input?

Lets suppose I have a circuit with a car battery, a switch and a led. The led will turn on when the switch is closed, and turn off if it's not. I want to remove the led from the circuit and put an ...
Guilherme's user avatar
  • 225
-3 votes
1 answer
176 views

Reading constant battery voltage and using the obtained value in sensor formula

there i am working on a project in which my system is connected to 3.7v~4.2V lithium battery, I have to read constant battery voltage irrespective of the current battery voltage and to do that I am ...
electro_nooobbbb's user avatar
20 votes
4 answers
106k views

What is the maximum power consumption of the Arduino Nano 3.0?

What is the maximum power consumption (in mW) of the Arduino Nano 3.0, when it is running in its default state (at 16MHz, no LEDs removed) and powered by an external regulated 5V supply so it bypasses ...
Nyxynyx's user avatar
  • 1,389
9 votes
1 answer
3k views

How can a 5v Uno talk to a 3.3v Due?

I currently have an Uno (which operates at 5v), and I'm looking at buying a Due (which only operates at 3.3v). I'd like to make them communicate via Serial or SPI or similar, but presumably connecting ...
Peter Bloomfield's user avatar
8 votes
2 answers
14k views

What maximum length of wire can I use to connect a push button to an Arduino?

I am trying to get 8 stop buttons to cause an Arduino UNO to activate a single relay! The stop buttons have been placed 30' to 250' away from the Arduino uno board. Q: How far can you go with 5v ...
The Earl's user avatar
  • 101
5 votes
2 answers
10k views

How to measure the supply voltage of Arduino without using an analog pin

I'm using Arduino Nano to measure temperature with a 10 kohm thermistor and a voltage divider. My problem is I'm getting only 4.2V on the 5V pin. The power is supplied via a USB cable from a desktop ...
dixhom's user avatar
  • 151
4 votes
2 answers
15k views

Convert Arduino Pro Mini 5v to use 3.3v

Id like to make my 5v pro mini use 3.3 v instead of 5 because i want to use it in an existing piece of electronics that uses 3v throughout. Looking at the specs for the pro mini it says the 3.3v ...
S Rosam's user avatar
  • 141
4 votes
1 answer
5k views

Precision voltmeter using Arduino

I am newbie, I need to measure precise voltage in range 0.00-0.80V, two digits precision. The voltage will not be greater than 1V-1.2V. I wonder if I need divider or not, I am sure that voltage ...
solderingiron's user avatar
3 votes
2 answers
6k views

Getting 3.3v on 5v pin in Arduino Uno

When interfacing my Arduino Uno with a relay I was facing reliability issues, and while investigating it with a multimeter, I found something strange. I noticed that in the 5V power pin (with which I ...
jrharshath's user avatar
3 votes
3 answers
2k views

WiFi module ESP8266 + Arduino Uno

I'm trying to connect a WiFi module, ESP8266-01 to an Arduino Uno. But, as I've understood, this module will only work with 3.3 V. Since all of the data pins use 5 V, one of the solutions is to use a ...
Artem's user avatar
  • 131
3 votes
2 answers
395 views

Does the square-wave nature of PWM dictate how much resistance you need?

I think the answer is yes, but I wanted to ask the question anyway for future common reference. And to check my understanding. Say I want to power 10 LEDs with PWM with my Mega 2560. I have a bunch ...
Aurast's user avatar
  • 285
2 votes
2 answers
13k views

HC-06 Bluetooth RX & TX voltage (3v3 || 5v)

I acquired a HC-06 Bluetooth module, and understand that the voltage on the pins must be 3v3 and therefore requires the use of a voltage divider to lower the Arduino's 5v to 3v3 like this. But the ...
user2983041's user avatar
2 votes
3 answers
7k views

How does the dual 5V and 3.3V output on the Uno R3 work exactly?

I'm constructing a circuit that needs both voltage supplies (for 3.3V RFID and 5V relay, GPS and screen) but the Uno is physically too big so I need to use a nano or mini pro, both of which I can only ...
Dan Bailey's user avatar
1 vote
1 answer
332 views

adc arduino using reference voltage to read stable/constant lithium battery voltage

I want to read my lithium battery voltage. I WANT TO CREATE A FUNCTION TO READ MY 3.7~4.2V,1200mAH BATTERY VOLTAGE THROUGH A MICROCONTROLLER (ARDUINO OR ATTINY44). THEN I WANT TO CALL THE CREATED ...
electro_nooobbbb's user avatar
1 vote
1 answer
167 views

ARDUINO DC Motor Control over IR Sensor INPUT

I'm working on a school project where I'm building a small convyeor belt using an ARDUINO, DC motor and IR sensor for moving object detection so my color sensor can read color value. I'm using single ...
Sunny Gavali's user avatar
1 vote
1 answer
871 views

YL-38 output to NodeMCU v1.0 analog input

Using a YL-38 and NodeMCU v1.0 I am trying to achieve what the first link is doing, take a soil moisture reading. I've done this on an arduino, but the conversion from an arduino nano to a nodemcu is ...
Doug Clark's user avatar
1 vote
2 answers
931 views

Why are MOSFETs only giving 8.1V for LEDs, not 12V?

I'm using three PWM outputs from an Arduino Mini Pro to drive the R/G/B parts of some strips of LEDs. The circuit is basically this: I've got a single 12V power supply, rated at 200W, to light the ...
Tim Morley's user avatar
1 vote
1 answer
3k views

Understanding flow of current with pull-up and pull-down circuits

I am new to all of this and was trying to figure out what was happening with pull-up/pull-down circuits. I think I understand what happens when the board handles the pull-up/pull-down but I wanted to ...
Brian's user avatar
  • 111
1 vote
2 answers
968 views

Measure Vcc using 1.1V bandgap

For an battery driven application I want to measure the Vcc (using an Atmega 32u4). That is my code: int readBandGap() { ADMUX = (B01 << REFS0) // VCC | (0 << ADLAR) // ...
Thomas S.'s user avatar
  • 566
1 vote
1 answer
885 views

Arduino 101 I/O voltage levels

As per the Arduino 101 schematic. The Arduino 101 has level shifters (TI make LSF0108) connected to the I/O ports I guess these are to make them Arduino compatible(5V) since the Intel Curie Module is ...
Miguel Sanchez's user avatar
0 votes
2 answers
1k views

Sensors go crazy on external power

For few days, I am trying to figure out, why my sensors do not work on external power. I bought NodeMCU along with couple different sensors etc. I was happily working with them, connecting them one by ...
ojek's user avatar
  • 121
0 votes
2 answers
943 views

Serial Communication between ESP8266 and Arduino ( Sofware and Hardware )

I wish to connect an Arduino ( any of 328P family ) which its 5v, with ESP8266 (ESP-01, or even NodeMCU or Wemos D1 mini ) which is 3v3 logic. My goal is that ESP8266 will be in-charge of MQTT ...
guyd's user avatar
  • 1,033
0 votes
2 answers
2k views

Reading a photoresistor

I have a wire with a 0-5v current. I want to detect if the current is there or not (HIGH/LOW.) I'm using an optocoupler to avoid putting too much current into my micro, as it is only a 3.3V micro. I'...
futurebird's user avatar
-1 votes
3 answers
203 views

Is that correct that input and output pins are not supposed to have current through them?

Are input and output pins not supposed to have current through them and only either apply voltage or "measure" it?
YakovL's user avatar
  • 153